Pfizer on Monday said that the European Medicines Agency lifted a warning on the smoking cessation therapy Champix (varenicline), regarding an increased risk of neuropsychiatric adverse events associated with the drug, known as Chantix in the US. The decision was based on data from the EAGLES post-marketing trial, which did not identify an increased risk of neuropsychiatric side effects linked to the therapy. Rory O'Connor, Pfizer's chief medical officer, remarked that "the new safety and efficacy information in the European label further supports the importance of Champix as a treatment option for healthcare providers and for those who are trying to quit smoking."

The EAGLES trial was jointly conducted by Pfizer and GlaxoSmithKline at the behest of and in consultation with the FDA and the EMA. In the trial, the results of which were published in The Lancet last month, did not show a significant increase in the incidence of the composite primary safety endpoint of serious neuropsychiatric adverse events with Chantix or Zyban compared to placebo and nicotine patch. The FDA stated that it is "reviewing the findings of this study and substantial supporting documentation from the clinical trial, along with additional published medical literature, as we continue to evaluate this issue.

Both, the EMA and FDA required Pfizer in 2009 to update the label of Champix to reflect that the therapy had been linked to "serious mental health events, including changes in behaviour, depressed mood, hostility, and suicidal thoughts."

Meanwhile, a spokeswoman for GlaxoSmithKline, whose anti-smoking treatment Zyban was also required by the EMA to include a label warning against suicidal ideation, noted that it is unclear whether the agency is lifting the warning from the drug's label.